Navigator Anna Ray, right, helps Maria Burciaga shop the federal marketplace for health insurance Saturday, March 1, 2014, at a Houston art gallery. March 31 is the deadline for open enrollment for people to take the plunge and purchase health insurance on the federal marketplace.(AP Photo/Pat Sullivan)

Navigator Anna Ray, right, helps Maria Burciaga shop the federal marketplace for health insurance Saturday, March 1, 2014, at a Houston art gallery. March 31 is the deadline for open enrollment for people to take the plunge and purchase health insurance on the federal marketplace.(AP Photo/Pat Sullivan)

A poster touting health insurance hangs on a door to a nearly empty room at a convention center in Texas City, Texas, Saturday, March 1, 2014. Though organizers had recruited assisters to handle as many as 400 people seeking help in navigating the federal insurance marketplace, only a handful had come by in the first hours of operations. (AP Photo/Pat Sullivan)

Health care assister Charolyn Mosley looks at her cell phone as she waits to help anyone looking to shop the federal marketplace for health insurance at a convention center in Texas City, Texas, Saturday, March 1, 2014. Though organizers had recruited assisters to handle as many as 400 people in navigating the federal insurance marketplace, only a handful had come by in the first hours of operations.(AP Photo/Pat Sullivan)

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HOUSTON (AP) â€” Sara Rodriguez recently received a $4,000 bill for a six-hour emergency room visit to treat a fever. She says she can’t pay, but she’s also not planning to buy health insurance through the new federal marketplace.

Rodriguez, like others gathered in a Houston gymnasium listening to a presentation about the health care overhaul, says she can’t afford insurance, even for $50 a month. With two young children and barely $400 of income a month after paying rent, she struggles to feed her family.

“It’s the law, but I’m not interested,” the 27-year-old says, explaining that she attended the presentation only because her GED teacher is making her write an essay. “I cannot afford it.”

The presentation ends and Rodriguez grabs her belongings and rushes out, forgoing the opportunity to make an appointment for enrollment assistance. The crowd of about 200 quickly dwindles, with some stragglers lingering to schedule appointments.

As a March 31 deadline draws near, this is a daily reality in Texas, where nearly 1 in 4 people is uninsured, the highest rate in the nation.

Texas stands out among the nation’s four most populous states for lagging behind on signups. California, New York and Florida have signed up far more people.

Enrollment helpers here are working days on end, sometimes with no time off, as they make a final push to get people to buy policies.

They count the small victories: If only five people come to a three-hour enrollment event but all sign up, that gets a thumbs’ up. No matter that it is just an infinitesimal fraction of the nearly 760,000 Texans the Department of Health and Human Services estimates could be eligible.

The final weeks of enrollment are sure to be filled with frenetic activity. Mega-enrollment drives are planned almost daily. Weekend and evening events are jam-packed. Hospitals in Dallas will stay open for longer weekday and weekend hours.

At this late stage, education and outreach have largely been abandoned. The goal now is to ensure that everyone who strolls in with paperwork walks out with insurance.

“Sign up! Sign up,” is the charge guiding Benjamin Hernandez, Houston’s deputy assistant health director, as he helps with a massive effort to reach his region’s 1 million uninsured.

Texas’ large uninsured population makes it crucial to the success of the entire national program. But the impediments are many.

The state’s large Hispanic population â€” some of whom are in the country illegally â€” are either not eligible or wary of enrolling because of fears that doing so might reveal the existence of family members at risk of being deported.

As of mid-March, enrollment numbers were only slightly more than 295,000, lagging behind Florida, another state with high numbers of uninsured and a governor opposed to the program.

Texas Gov. Rick Perry has erected his own obstacles in the form of additional rules and training requirements imposed on health care “navigators.”

Other Texas Republicans have also slammed the program. Lt. Gov. David Dewhurst, forced into a runoff against a tea party candidate after a tight primary, released a TV ad that shows businessmen and women in suits engaged in a high school cafeteria food fight â€” a metaphor, according to the ad, for the program’s glitch-filled rollout.

It’s not clear whether the Perry mandates and the intense public criticism of the law have scared off many potential enrollees. But Hernandez believes “lack of information and misinformation are key barriers.”

Brenda Sanders, 54, was one of about a half-dozen people who trickled into a recent enrollment event on Houston’s north side. Sanders knew the deadline and where to find a plan. She tried to apply, and it appeared she didn’t qualify for financial assistance. The $200 monthly premium offered was unaffordable on her income of barely $600 a month, the part-time home care provider said.

“I’m a little disappointed,” Sanders said. “Even with Obamacare, it’s supposed to be affordable, but for people like me, that are low, low income, it’s still not affordable.”

And that is another struggle for Texas. The state decided against expanding Medicaid, despite the offer of federal dollars to help cover the costs in the first few years, meaning more than 1 million of the uninsured who do not qualify for subsidies could be left without coverage.

In the meantime, Houston and other areas are zeroing in on crucial populations: younger people and Hispanics. Houston spent about $40,000 on a two-week radio ad buy in English and Spanish. Hernandez also advertised in fitness centers, hoping to reach Hispanic mothers, believed to be the health care decision makers in those families.